prometheus/index/index.go

1093 lines
27 KiB
Go

// Copyright 2017 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package index
import (
"bufio"
"encoding/binary"
"hash"
"hash/crc32"
"io"
"io/ioutil"
"math"
"os"
"path/filepath"
"sort"
"strings"
"github.com/pkg/errors"
"github.com/prometheus/tsdb/chunks"
"github.com/prometheus/tsdb/encoding"
"github.com/prometheus/tsdb/fileutil"
"github.com/prometheus/tsdb/labels"
)
const (
// MagicIndex 4 bytes at the head of an index file.
MagicIndex = 0xBAAAD700
// HeaderLen represents number of bytes reserved of index for header.
HeaderLen = 5
// FormatV1 represents 1 version of index.
FormatV1 = 1
// FormatV2 represents 2 version of index.
FormatV2 = 2
labelNameSeperator = "\xff"
indexFilename = "index"
)
type indexWriterSeries struct {
labels labels.Labels
chunks []chunks.Meta // series file offset of chunks
offset uint32 // index file offset of series reference
}
type indexWriterSeriesSlice []*indexWriterSeries
func (s indexWriterSeriesSlice) Len() int { return len(s) }
func (s indexWriterSeriesSlice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s indexWriterSeriesSlice) Less(i, j int) bool {
return labels.Compare(s[i].labels, s[j].labels) < 0
}
type indexWriterStage uint8
const (
idxStageNone indexWriterStage = iota
idxStageSymbols
idxStageSeries
idxStageLabelIndex
idxStagePostings
idxStageDone
)
func (s indexWriterStage) String() string {
switch s {
case idxStageNone:
return "none"
case idxStageSymbols:
return "symbols"
case idxStageSeries:
return "series"
case idxStageLabelIndex:
return "label index"
case idxStagePostings:
return "postings"
case idxStageDone:
return "done"
}
return "<unknown>"
}
// The table gets initialized with sync.Once but may still cause a race
// with any other use of the crc32 package anywhere. Thus we initialize it
// before.
var castagnoliTable *crc32.Table
func init() {
castagnoliTable = crc32.MakeTable(crc32.Castagnoli)
}
// newCRC32 initializes a CRC32 hash with a preconfigured polynomial, so the
// polynomial may be easily changed in one location at a later time, if necessary.
func newCRC32() hash.Hash32 {
return crc32.New(castagnoliTable)
}
// Writer implements the IndexWriter interface for the standard
// serialization format.
type Writer struct {
f *os.File
fbuf *bufio.Writer
pos uint64
toc TOC
stage indexWriterStage
// Reusable memory.
buf1 encoding.Encbuf
buf2 encoding.Encbuf
uint32s []uint32
symbols map[string]uint32 // symbol offsets
seriesOffsets map[uint64]uint64 // offsets of series
labelIndexes []hashEntry // label index offsets
postings []hashEntry // postings lists offsets
// Hold last series to validate that clients insert new series in order.
lastSeries labels.Labels
crc32 hash.Hash
Version int
}
// TOC represents index Table Of Content that states where each section of index starts.
type TOC struct {
Symbols uint64
Series uint64
LabelIndices uint64
LabelIndicesTable uint64
Postings uint64
PostingsTable uint64
}
// NewTOCFromByteSlice return parsed TOC from given index byte slice.
func NewTOCFromByteSlice(bs ByteSlice) (*TOC, error) {
if bs.Len() < indexTOCLen {
return nil, encoding.ErrInvalidSize
}
b := bs.Range(bs.Len()-indexTOCLen, bs.Len())
expCRC := binary.BigEndian.Uint32(b[len(b)-4:])
d := encoding.Decbuf{B: b[:len(b)-4]}
if d.Crc32(castagnoliTable) != expCRC {
return nil, errors.Wrap(encoding.ErrInvalidChecksum, "read TOC")
}
if err := d.Err(); err != nil {
return nil, err
}
return &TOC{
Symbols: d.Be64(),
Series: d.Be64(),
LabelIndices: d.Be64(),
LabelIndicesTable: d.Be64(),
Postings: d.Be64(),
PostingsTable: d.Be64(),
}, nil
}
// NewWriter returns a new Writer to the given filename. It serializes data in format version 2.
func NewWriter(fn string) (*Writer, error) {
dir := filepath.Dir(fn)
df, err := fileutil.OpenDir(dir)
if err != nil {
return nil, err
}
defer df.Close() // Close for platform windows.
if err := os.RemoveAll(fn); err != nil {
return nil, errors.Wrap(err, "remove any existing index at path")
}
f, err := os.OpenFile(fn, os.O_CREATE|os.O_WRONLY, 0666)
if err != nil {
return nil, err
}
if err := fileutil.Fsync(df); err != nil {
return nil, errors.Wrap(err, "sync dir")
}
iw := &Writer{
f: f,
fbuf: bufio.NewWriterSize(f, 1<<22),
pos: 0,
stage: idxStageNone,
// Reusable memory.
buf1: encoding.Encbuf{B: make([]byte, 0, 1<<22)},
buf2: encoding.Encbuf{B: make([]byte, 0, 1<<22)},
uint32s: make([]uint32, 0, 1<<15),
// Caches.
symbols: make(map[string]uint32, 1<<13),
seriesOffsets: make(map[uint64]uint64, 1<<16),
crc32: newCRC32(),
}
if err := iw.writeMeta(); err != nil {
return nil, err
}
return iw, nil
}
func (w *Writer) write(bufs ...[]byte) error {
for _, b := range bufs {
n, err := w.fbuf.Write(b)
w.pos += uint64(n)
if err != nil {
return err
}
// For now the index file must not grow beyond 64GiB. Some of the fixed-sized
// offset references in v1 are only 4 bytes large.
// Once we move to compressed/varint representations in those areas, this limitation
// can be lifted.
if w.pos > 16*math.MaxUint32 {
return errors.Errorf("exceeding max size of 64GiB")
}
}
return nil
}
// addPadding adds zero byte padding until the file size is a multiple size.
func (w *Writer) addPadding(size int) error {
p := w.pos % uint64(size)
if p == 0 {
return nil
}
p = uint64(size) - p
return errors.Wrap(w.write(make([]byte, p)), "add padding")
}
// ensureStage handles transitions between write stages and ensures that IndexWriter
// methods are called in an order valid for the implementation.
func (w *Writer) ensureStage(s indexWriterStage) error {
if w.stage == s {
return nil
}
if w.stage > s {
return errors.Errorf("invalid stage %q, currently at %q", s, w.stage)
}
// Mark start of sections in table of contents.
switch s {
case idxStageSymbols:
w.toc.Symbols = w.pos
case idxStageSeries:
w.toc.Series = w.pos
case idxStageLabelIndex:
w.toc.LabelIndices = w.pos
case idxStagePostings:
w.toc.Postings = w.pos
case idxStageDone:
w.toc.LabelIndicesTable = w.pos
if err := w.writeOffsetTable(w.labelIndexes); err != nil {
return err
}
w.toc.PostingsTable = w.pos
if err := w.writeOffsetTable(w.postings); err != nil {
return err
}
if err := w.writeTOC(); err != nil {
return err
}
}
w.stage = s
return nil
}
func (w *Writer) writeMeta() error {
w.buf1.Reset()
w.buf1.PutBE32(MagicIndex)
w.buf1.PutByte(FormatV2)
return w.write(w.buf1.Get())
}
// AddSeries adds the series one at a time along with its chunks.
func (w *Writer) AddSeries(ref uint64, lset labels.Labels, chunks ...chunks.Meta) error {
if err := w.ensureStage(idxStageSeries); err != nil {
return err
}
if labels.Compare(lset, w.lastSeries) <= 0 {
return errors.Errorf("out-of-order series added with label set %q", lset)
}
if _, ok := w.seriesOffsets[ref]; ok {
return errors.Errorf("series with reference %d already added", ref)
}
// We add padding to 16 bytes to increase the addressable space we get through 4 byte
// series references.
if err := w.addPadding(16); err != nil {
return errors.Errorf("failed to write padding bytes: %v", err)
}
if w.pos%16 != 0 {
return errors.Errorf("series write not 16-byte aligned at %d", w.pos)
}
w.seriesOffsets[ref] = w.pos / 16
w.buf2.Reset()
w.buf2.PutUvarint(len(lset))
for _, l := range lset {
// here we have an index for the symbol file if v2, otherwise it's an offset
index, ok := w.symbols[l.Name]
if !ok {
return errors.Errorf("symbol entry for %q does not exist", l.Name)
}
w.buf2.PutUvarint32(index)
index, ok = w.symbols[l.Value]
if !ok {
return errors.Errorf("symbol entry for %q does not exist", l.Value)
}
w.buf2.PutUvarint32(index)
}
w.buf2.PutUvarint(len(chunks))
if len(chunks) > 0 {
c := chunks[0]
w.buf2.PutVarint64(c.MinTime)
w.buf2.PutUvarint64(uint64(c.MaxTime - c.MinTime))
w.buf2.PutUvarint64(c.Ref)
t0 := c.MaxTime
ref0 := int64(c.Ref)
for _, c := range chunks[1:] {
w.buf2.PutUvarint64(uint64(c.MinTime - t0))
w.buf2.PutUvarint64(uint64(c.MaxTime - c.MinTime))
t0 = c.MaxTime
w.buf2.PutVarint64(int64(c.Ref) - ref0)
ref0 = int64(c.Ref)
}
}
w.buf1.Reset()
w.buf1.PutUvarint(w.buf2.Len())
w.buf2.PutHash(w.crc32)
if err := w.write(w.buf1.Get(), w.buf2.Get()); err != nil {
return errors.Wrap(err, "write series data")
}
w.lastSeries = append(w.lastSeries[:0], lset...)
return nil
}
func (w *Writer) AddSymbols(sym map[string]struct{}) error {
if err := w.ensureStage(idxStageSymbols); err != nil {
return err
}
// Generate sorted list of strings we will store as reference table.
symbols := make([]string, 0, len(sym))
for s := range sym {
symbols = append(symbols, s)
}
sort.Strings(symbols)
w.buf1.Reset()
w.buf2.Reset()
w.buf2.PutBE32int(len(symbols))
w.symbols = make(map[string]uint32, len(symbols))
for index, s := range symbols {
w.symbols[s] = uint32(index)
w.buf2.PutUvarintStr(s)
}
w.buf1.PutBE32int(w.buf2.Len())
w.buf2.PutHash(w.crc32)
err := w.write(w.buf1.Get(), w.buf2.Get())
return errors.Wrap(err, "write symbols")
}
func (w *Writer) WriteLabelIndex(names []string, values []string) error {
if len(values)%len(names) != 0 {
return errors.Errorf("invalid value list length %d for %d names", len(values), len(names))
}
if err := w.ensureStage(idxStageLabelIndex); err != nil {
return errors.Wrap(err, "ensure stage")
}
valt, err := NewStringTuples(values, len(names))
if err != nil {
return err
}
sort.Sort(valt)
// Align beginning to 4 bytes for more efficient index list scans.
if err := w.addPadding(4); err != nil {
return err
}
w.labelIndexes = append(w.labelIndexes, hashEntry{
keys: names,
offset: w.pos,
})
w.buf2.Reset()
w.buf2.PutBE32int(len(names))
w.buf2.PutBE32int(valt.Len())
// here we have an index for the symbol file if v2, otherwise it's an offset
for _, v := range valt.entries {
index, ok := w.symbols[v]
if !ok {
return errors.Errorf("symbol entry for %q does not exist", v)
}
w.buf2.PutBE32(index)
}
w.buf1.Reset()
w.buf1.PutBE32int(w.buf2.Len())
w.buf2.PutHash(w.crc32)
err = w.write(w.buf1.Get(), w.buf2.Get())
return errors.Wrap(err, "write label index")
}
// writeOffsetTable writes a sequence of readable hash entries.
func (w *Writer) writeOffsetTable(entries []hashEntry) error {
w.buf2.Reset()
w.buf2.PutBE32int(len(entries))
for _, e := range entries {
w.buf2.PutUvarint(len(e.keys))
for _, k := range e.keys {
w.buf2.PutUvarintStr(k)
}
w.buf2.PutUvarint64(e.offset)
}
w.buf1.Reset()
w.buf1.PutBE32int(w.buf2.Len())
w.buf2.PutHash(w.crc32)
return w.write(w.buf1.Get(), w.buf2.Get())
}
const indexTOCLen = 6*8 + 4
func (w *Writer) writeTOC() error {
w.buf1.Reset()
w.buf1.PutBE64(w.toc.Symbols)
w.buf1.PutBE64(w.toc.Series)
w.buf1.PutBE64(w.toc.LabelIndices)
w.buf1.PutBE64(w.toc.LabelIndicesTable)
w.buf1.PutBE64(w.toc.Postings)
w.buf1.PutBE64(w.toc.PostingsTable)
w.buf1.PutHash(w.crc32)
return w.write(w.buf1.Get())
}
func (w *Writer) WritePostings(name, value string, it Postings) error {
if err := w.ensureStage(idxStagePostings); err != nil {
return errors.Wrap(err, "ensure stage")
}
// Align beginning to 4 bytes for more efficient postings list scans.
if err := w.addPadding(4); err != nil {
return err
}
w.postings = append(w.postings, hashEntry{
keys: []string{name, value},
offset: w.pos,
})
// Order of the references in the postings list does not imply order
// of the series references within the persisted block they are mapped to.
// We have to sort the new references again.
refs := w.uint32s[:0]
for it.Next() {
offset, ok := w.seriesOffsets[it.At()]
if !ok {
return errors.Errorf("%p series for reference %d not found", w, it.At())
}
if offset > (1<<32)-1 {
return errors.Errorf("series offset %d exceeds 4 bytes", offset)
}
refs = append(refs, uint32(offset))
}
if err := it.Err(); err != nil {
return err
}
sort.Sort(uint32slice(refs))
w.buf2.Reset()
w.buf2.PutBE32int(len(refs))
for _, r := range refs {
w.buf2.PutBE32(r)
}
w.uint32s = refs
w.buf1.Reset()
w.buf1.PutBE32int(w.buf2.Len())
w.buf2.PutHash(w.crc32)
err := w.write(w.buf1.Get(), w.buf2.Get())
return errors.Wrap(err, "write postings")
}
type uint32slice []uint32
func (s uint32slice) Len() int { return len(s) }
func (s uint32slice) Swap(i, j int) { s[i], s[j] = s[j], s[i] }
func (s uint32slice) Less(i, j int) bool { return s[i] < s[j] }
type hashEntry struct {
keys []string
offset uint64
}
func (w *Writer) Close() error {
if err := w.ensureStage(idxStageDone); err != nil {
return err
}
if err := w.fbuf.Flush(); err != nil {
return err
}
if err := fileutil.Fsync(w.f); err != nil {
return err
}
return w.f.Close()
}
// StringTuples provides access to a sorted list of string tuples.
type StringTuples interface {
// Total number of tuples in the list.
Len() int
// At returns the tuple at position i.
At(i int) ([]string, error)
}
type Reader struct {
b ByteSlice
// Close that releases the underlying resources of the byte slice.
c io.Closer
// Cached hashmaps of section offsets.
labels map[string]uint64
// LabelName to LabelValue to offset map.
postings map[string]map[string]uint64
// Cache of read symbols. Strings that are returned when reading from the
// block are always backed by true strings held in here rather than
// strings that are backed by byte slices from the mmap'd index file. This
// prevents memory faults when applications work with read symbols after
// the block has been unmapped. The older format has sparse indexes so a map
// must be used, but the new format is not so we can use a slice.
symbolsV1 map[uint32]string
symbolsV2 []string
symbolsTableSize uint64
dec *Decoder
version int
}
// ByteSlice abstracts a byte slice.
type ByteSlice interface {
Len() int
Range(start, end int) []byte
}
type realByteSlice []byte
func (b realByteSlice) Len() int {
return len(b)
}
func (b realByteSlice) Range(start, end int) []byte {
return b[start:end]
}
func (b realByteSlice) Sub(start, end int) ByteSlice {
return b[start:end]
}
// NewReader returns a new index reader on the given byte slice. It automatically
// handles different format versions.
func NewReader(b ByteSlice) (*Reader, error) {
return newReader(b, ioutil.NopCloser(nil))
}
// NewFileReader returns a new index reader against the given index file.
func NewFileReader(path string) (*Reader, error) {
f, err := fileutil.OpenMmapFile(path)
if err != nil {
return nil, err
}
return newReader(realByteSlice(f.Bytes()), f)
}
func newReader(b ByteSlice, c io.Closer) (*Reader, error) {
r := &Reader{
b: b,
c: c,
labels: map[string]uint64{},
postings: map[string]map[string]uint64{},
}
// Verify header.
if r.b.Len() < HeaderLen {
return nil, errors.Wrap(encoding.ErrInvalidSize, "index header")
}
if m := binary.BigEndian.Uint32(r.b.Range(0, 4)); m != MagicIndex {
return nil, errors.Errorf("invalid magic number %x", m)
}
r.version = int(r.b.Range(4, 5)[0])
if r.version != FormatV1 && r.version != FormatV2 {
return nil, errors.Errorf("unknown index file version %d", r.version)
}
toc, err := NewTOCFromByteSlice(b)
if err != nil {
return nil, errors.Wrap(err, "read TOC")
}
r.symbolsV2, r.symbolsV1, err = ReadSymbols(r.b, r.version, int(toc.Symbols))
if err != nil {
return nil, errors.Wrap(err, "read symbols")
}
// Use the strings already allocated by symbols, rather than
// re-allocating them again below.
// Additionally, calculate symbolsTableSize.
allocatedSymbols := make(map[string]string, len(r.symbolsV1)+len(r.symbolsV2))
for _, s := range r.symbolsV1 {
r.symbolsTableSize += uint64(len(s) + 8)
allocatedSymbols[s] = s
}
for _, s := range r.symbolsV2 {
r.symbolsTableSize += uint64(len(s) + 8)
allocatedSymbols[s] = s
}
if err := ReadOffsetTable(r.b, toc.LabelIndicesTable, func(key []string, off uint64) error {
if len(key) != 1 {
return errors.Errorf("unexpected key length for label indices table %d", len(key))
}
r.labels[allocatedSymbols[key[0]]] = off
return nil
}); err != nil {
return nil, errors.Wrap(err, "read label index table")
}
r.postings[""] = map[string]uint64{}
if err := ReadOffsetTable(r.b, toc.PostingsTable, func(key []string, off uint64) error {
if len(key) != 2 {
return errors.Errorf("unexpected key length for posting table %d", len(key))
}
if _, ok := r.postings[key[0]]; !ok {
r.postings[allocatedSymbols[key[0]]] = map[string]uint64{}
}
r.postings[key[0]][allocatedSymbols[key[1]]] = off
return nil
}); err != nil {
return nil, errors.Wrap(err, "read postings table")
}
r.dec = &Decoder{LookupSymbol: r.lookupSymbol}
return r, nil
}
// Version returns the file format version of the underlying index.
func (r *Reader) Version() int {
return r.version
}
// Range marks a byte range.
type Range struct {
Start, End int64
}
// PostingsRanges returns a new map of byte range in the underlying index file
// for all postings lists.
func (r *Reader) PostingsRanges() (map[labels.Label]Range, error) {
m := map[labels.Label]Range{}
for k, e := range r.postings {
for v, start := range e {
d := encoding.NewDecbufAt(r.b, int(start), castagnoliTable)
if d.Err() != nil {
return nil, d.Err()
}
m[labels.Label{Name: k, Value: v}] = Range{
Start: int64(start) + 4,
End: int64(start) + 4 + int64(d.Len()),
}
}
}
return m, nil
}
// ReadSymbols reads the symbol table fully into memory and allocates proper strings for them.
// Strings backed by the mmap'd memory would cause memory faults if applications keep using them
// after the reader is closed.
func ReadSymbols(bs ByteSlice, version int, off int) ([]string, map[uint32]string, error) {
if off == 0 {
return nil, nil, nil
}
d := encoding.NewDecbufAt(bs, off, castagnoliTable)
var (
origLen = d.Len()
cnt = d.Be32int()
basePos = uint32(off) + 4
nextPos = basePos + uint32(origLen-d.Len())
symbolSlice []string
symbols = map[uint32]string{}
)
if version == FormatV2 {
symbolSlice = make([]string, 0, cnt)
}
for d.Err() == nil && d.Len() > 0 && cnt > 0 {
s := d.UvarintStr()
if version == FormatV2 {
symbolSlice = append(symbolSlice, s)
} else {
symbols[nextPos] = s
nextPos = basePos + uint32(origLen-d.Len())
}
cnt--
}
return symbolSlice, symbols, errors.Wrap(d.Err(), "read symbols")
}
// ReadOffsetTable reads an offset table and at the given position calls f for each
// found entry. If f returns an error it stops decoding and returns the received error.
func ReadOffsetTable(bs ByteSlice, off uint64, f func([]string, uint64) error) error {
d := encoding.NewDecbufAt(bs, int(off), castagnoliTable)
cnt := d.Be32()
for d.Err() == nil && d.Len() > 0 && cnt > 0 {
keyCount := d.Uvarint()
keys := make([]string, 0, keyCount)
for i := 0; i < keyCount; i++ {
keys = append(keys, d.UvarintStr())
}
o := d.Uvarint64()
if d.Err() != nil {
break
}
if err := f(keys, o); err != nil {
return err
}
cnt--
}
return d.Err()
}
// Close the reader and its underlying resources.
func (r *Reader) Close() error {
return r.c.Close()
}
func (r *Reader) lookupSymbol(o uint32) (string, error) {
if int(o) < len(r.symbolsV2) {
return r.symbolsV2[o], nil
}
s, ok := r.symbolsV1[o]
if !ok {
return "", errors.Errorf("unknown symbol offset %d", o)
}
return s, nil
}
// Symbols returns a set of symbols that exist within the index.
func (r *Reader) Symbols() (map[string]struct{}, error) {
res := make(map[string]struct{}, len(r.symbolsV1)+len(r.symbolsV2))
for _, s := range r.symbolsV1 {
res[s] = struct{}{}
}
for _, s := range r.symbolsV2 {
res[s] = struct{}{}
}
return res, nil
}
// SymbolTableSize returns the symbol table size in bytes.
func (r *Reader) SymbolTableSize() uint64 {
return r.symbolsTableSize
}
// LabelValues returns value tuples that exist for the given label name tuples.
func (r *Reader) LabelValues(names ...string) (StringTuples, error) {
key := strings.Join(names, labelNameSeperator)
off, ok := r.labels[key]
if !ok {
// XXX(fabxc): hot fix. Should return a partial data error and handle cases
// where the entire block has no data gracefully.
return emptyStringTuples{}, nil
//return nil, fmt.Errorf("label index doesn't exist")
}
d := encoding.NewDecbufAt(r.b, int(off), castagnoliTable)
nc := d.Be32int()
d.Be32() // consume unused value entry count.
if d.Err() != nil {
return nil, errors.Wrap(d.Err(), "read label value index")
}
st := &serializedStringTuples{
idsCount: nc,
idsBytes: d.Get(),
lookup: r.lookupSymbol,
}
return st, nil
}
type emptyStringTuples struct{}
func (emptyStringTuples) At(i int) ([]string, error) { return nil, nil }
func (emptyStringTuples) Len() int { return 0 }
// LabelIndices returns a slice of label names for which labels or label tuples value indices exist.
// NOTE: This is deprecated. Use `LabelNames()` instead.
func (r *Reader) LabelIndices() ([][]string, error) {
var res [][]string
for s := range r.labels {
res = append(res, strings.Split(s, labelNameSeperator))
}
return res, nil
}
// Series reads the series with the given ID and writes its labels and chunks into lbls and chks.
func (r *Reader) Series(id uint64, lbls *labels.Labels, chks *[]chunks.Meta) error {
offset := id
// In version 2 series IDs are no longer exact references but series are 16-byte padded
// and the ID is the multiple of 16 of the actual position.
if r.version == FormatV2 {
offset = id * 16
}
d := encoding.NewDecbufUvarintAt(r.b, int(offset), castagnoliTable)
if d.Err() != nil {
return d.Err()
}
return errors.Wrap(r.dec.Series(d.Get(), lbls, chks), "read series")
}
// Postings returns a postings list for the given label pair.
func (r *Reader) Postings(name, value string) (Postings, error) {
e, ok := r.postings[name]
if !ok {
return EmptyPostings(), nil
}
off, ok := e[value]
if !ok {
return EmptyPostings(), nil
}
d := encoding.NewDecbufAt(r.b, int(off), castagnoliTable)
if d.Err() != nil {
return nil, errors.Wrap(d.Err(), "get postings entry")
}
_, p, err := r.dec.Postings(d.Get())
if err != nil {
return nil, errors.Wrap(err, "decode postings")
}
return p, nil
}
// SortedPostings returns the given postings list reordered so that the backing series
// are sorted.
func (r *Reader) SortedPostings(p Postings) Postings {
return p
}
// Size returns the size of an index file.
func (r *Reader) Size() int64 {
return int64(r.b.Len())
}
// LabelNames returns all the unique label names present in the index.
func (r *Reader) LabelNames() ([]string, error) {
labelNamesMap := make(map[string]struct{}, len(r.labels))
for key := range r.labels {
// 'key' contains the label names concatenated with the
// delimiter 'labelNameSeperator'.
names := strings.Split(key, labelNameSeperator)
for _, name := range names {
if name == allPostingsKey.Name {
// This is not from any metric.
// It is basically an empty label name.
continue
}
labelNamesMap[name] = struct{}{}
}
}
labelNames := make([]string, 0, len(labelNamesMap))
for name := range labelNamesMap {
labelNames = append(labelNames, name)
}
sort.Strings(labelNames)
return labelNames, nil
}
type stringTuples struct {
length int // tuple length
entries []string // flattened tuple entries
}
func NewStringTuples(entries []string, length int) (*stringTuples, error) {
if len(entries)%length != 0 {
return nil, errors.Wrap(encoding.ErrInvalidSize, "string tuple list")
}
return &stringTuples{entries: entries, length: length}, nil
}
func (t *stringTuples) Len() int { return len(t.entries) / t.length }
func (t *stringTuples) At(i int) ([]string, error) { return t.entries[i : i+t.length], nil }
func (t *stringTuples) Swap(i, j int) {
c := make([]string, t.length)
copy(c, t.entries[i:i+t.length])
for k := 0; k < t.length; k++ {
t.entries[i+k] = t.entries[j+k]
t.entries[j+k] = c[k]
}
}
func (t *stringTuples) Less(i, j int) bool {
for k := 0; k < t.length; k++ {
d := strings.Compare(t.entries[i+k], t.entries[j+k])
if d < 0 {
return true
}
if d > 0 {
return false
}
}
return false
}
type serializedStringTuples struct {
idsCount int
idsBytes []byte // bytes containing the ids pointing to the string in the lookup table.
lookup func(uint32) (string, error)
}
func (t *serializedStringTuples) Len() int {
return len(t.idsBytes) / (4 * t.idsCount)
}
func (t *serializedStringTuples) At(i int) ([]string, error) {
if len(t.idsBytes) < (i+t.idsCount)*4 {
return nil, encoding.ErrInvalidSize
}
res := make([]string, 0, t.idsCount)
for k := 0; k < t.idsCount; k++ {
offset := binary.BigEndian.Uint32(t.idsBytes[(i+k)*4:])
s, err := t.lookup(offset)
if err != nil {
return nil, errors.Wrap(err, "symbol lookup")
}
res = append(res, s)
}
return res, nil
}
// Decoder provides decoding methods for the v1 and v2 index file format.
//
// It currently does not contain decoding methods for all entry types but can be extended
// by them if there's demand.
type Decoder struct {
LookupSymbol func(uint32) (string, error)
}
// Postings returns a postings list for b and its number of elements.
func (dec *Decoder) Postings(b []byte) (int, Postings, error) {
d := encoding.Decbuf{B: b}
n := d.Be32int()
l := d.Get()
return n, newBigEndianPostings(l), d.Err()
}
// Series decodes a series entry from the given byte slice into lset and chks.
func (dec *Decoder) Series(b []byte, lbls *labels.Labels, chks *[]chunks.Meta) error {
*lbls = (*lbls)[:0]
*chks = (*chks)[:0]
d := encoding.Decbuf{B: b}
k := d.Uvarint()
for i := 0; i < k; i++ {
lno := uint32(d.Uvarint())
lvo := uint32(d.Uvarint())
if d.Err() != nil {
return errors.Wrap(d.Err(), "read series label offsets")
}
ln, err := dec.LookupSymbol(lno)
if err != nil {
return errors.Wrap(err, "lookup label name")
}
lv, err := dec.LookupSymbol(lvo)
if err != nil {
return errors.Wrap(err, "lookup label value")
}
*lbls = append(*lbls, labels.Label{Name: ln, Value: lv})
}
// Read the chunks meta data.
k = d.Uvarint()
if k == 0 {
return nil
}
t0 := d.Varint64()
maxt := int64(d.Uvarint64()) + t0
ref0 := int64(d.Uvarint64())
*chks = append(*chks, chunks.Meta{
Ref: uint64(ref0),
MinTime: t0,
MaxTime: maxt,
})
t0 = maxt
for i := 1; i < k; i++ {
mint := int64(d.Uvarint64()) + t0
maxt := int64(d.Uvarint64()) + mint
ref0 += d.Varint64()
t0 = maxt
if d.Err() != nil {
return errors.Wrapf(d.Err(), "read meta for chunk %d", i)
}
*chks = append(*chks, chunks.Meta{
Ref: uint64(ref0),
MinTime: mint,
MaxTime: maxt,
})
}
return d.Err()
}